Bobebt e



'Ressued Aug. i 13, 1929.

UNITE sTATEs-P'ATENT orFlcE.

noBET n xITToN,

In vALvn or SALT lLAKE CITY, UTAH, .AssIeNom BY V:msnm Ass'IG'NIENTs,

To :NTERNATIONAL AIR BRAKE COMPANY.

original m. 1,599,619, dated september 14, 192e, serial N o. 74,204, med December s, 192:5. applicatie for remue mea August ze, 192s.- serm ma. 302,878.

My invention relates to valves Vand has for its object to provide a new and eiclent automatic valve or controlling air.

A further object is to provide a valve whereby lthe pressure ofV compressed -air through air lines, in either direction, may be automatically maintained, released or applied to control mechanical movements and tol overcome momentum, and particularly to provide a quick acting automatic control valve for air ybrake mechanism `on automo .biles and other conveyances.

Also to control the distribution of power to such conveyances. 4 l

These objects" I accomplish with the device illustrated in the accompanying drawings 1n which similar letters and numerals of reference indicate like parts throughout the'several views and as described in the specification forming a part of this applica- I tion and pointed out in the appended claims,

the best and most substantial embodimentit beingunderstood that slig t changes and modifications may e made in construction Without departing from the spirit of the inventionas set out in the claims. r

In the drawings in which I have shown of my invention, Figure 1 is an elevation of my valve with parts cut away. Figure 2 is a longitudinal diametrical section fof" the valve. Figure 3 is the same section as shown in Figure 2 with ythe valve 21 closed and the--valve 14 open.

Ino the drawings I have shown the major portion of my Valve enclosed in a cylindrical casing A, which has closure caps 1 and 2 screwed on the ends thereof. A hollow pisf ton rod-B is slidably carried in the casing A, which rod and its connections form the other portion of my valve. On one end of said .piston rod B a closure cap 12 is screwed `having'ports '12 boredthercthrough to allow passage of air, when air escapement is required in the operation of the valve. The

other endof the piston rod B is fastened centrally in a piston C which is operatively carried in -the casing A and divides the interiorof said casing A into two compartments 3 and 4. A main spiral spring 5 is carried in compartment 4, with one end of the springbearing against the piston C and .therother end against the closure cap l2. An

inner casing y6 is concentricallysecured toN ingthem to move in the opposite direction,

and one end of a flexible air tube `29 is securedon the free'end of the casing 6. -A cylindricalor sleeve nut 8 is integrally formed on and concentric 'with said piston C within which ilange or sleeve nut 8 the endy portion of said casing is screwed, and in the opposite portion of said flange or sleeve nut 8 is screwed the end of the piston rod B.

The end of the sleeve nut 8 in4 which the piston rod B is screwed is externally threaded to receive the packing washer 10 and the jam nut'll which holds the washer and v packing in place on the piston assembly C.

The sald piston C is centrally bored and cut to form a valve seat 13 infwhich the valve 14 normally seats. The valve 14 has` a valve stem 15 secured centrally thereto and said stem is enlarged at 16 to form a guide which is longitudinally slidable in the said piston rod B. IIoles 17 are provided in the enlarged guide 16 to allow passage of' air therethrough. The other end Vportion of said valve stem 15 is externally threaded to receive the suitably packed piston head 18 which is the same size as the guide 16 and is also longitudinally slidable in the said piston rod B and which piston head 18v guides the valve stem 15 longitudinally within the said piston rod B. 'The said valve'stexn 15 is centrally bored for a portion of its length to receive the' valve stem E with the edge of the bore chamfered to 'form a valve seat` 19. Ports 2Q are bored in the wall of the internally bored portion of the said valve stem 15 to allow passage of airtherethrough. A valve 21 is'formed on the valve stem E and when the stem is operated the valve 21 engages in the valve seat 1 9. One end portion of the said valve stem E is enlarged to form a guide 22 which is longitudinally slidable in the internally bored portion of the valve stemv 15 and which acts as a support for the one end of the valve stem E. The other end of the said valve stem is slidably carried in the closure cap 12 of the piston rod B, and the extreme end of said valve stem E is enlarged and internally threaded to receive an eye bolt 23. The said eye bolt 23 is provided so that a lever may be connected therewith for operating the valves 21 and 14. Thussaid rod- E forms a control element for the valve member 21, and the eye bolt 23 forms z a control member carried by said rod exlpq teriorly of the parts A and B. A spiral spring 24 is carried within the said piston rod B between the guide 16 and the piston C to normally hold the valve\14 in its seat 13. An air connection 25 is provided onl one side of the said piston rod B to which a brake line may be attached tocarry the air to the desired places of use.y A branch air connection 26 is yprovided on the side of 25 'and a similar connection 27 is provided in the'side of the chamber 3.of the casing A to which connections a flexible air tube 28 is attached to carry back-pressure of air to the chamber 3 from the air connection 25. In the operation of my valve, pressure is applied at the eye bolt 23 in orderto move the stem E longitudinally. This operation `results in the closing of the exhaust valve 21 -and the opening of the intake valve 14, which allows air to enter at the intake valve 30 14 and flow past or around the same, through the ports 17 in the guide 16 and into the tubular piston rod B, and against the piston head 18, through theports 20 of the valve stem 15 and against the closure `side of the exhaust valVeA21, -out through the passage 25 to the mechanism to be operated, and also by way ofthe flexible connection 28 into the automat-ic chamber 3. This produces a downward pressure on the piston C, with its valve seat 13, and shuts olf the air lflow when sufficient pressure is induced to compress the main spring 5 far enough to allow the valve 14 to seat. At the same time a. restraining pressure is thrown against piston 18 in the hollow pis,- ton rod B in order to prevent the involuntary tendency to over apply the pressure by the reoceding action of the piston, C. It is evident that shoulda further movement of ,J p the valve mechanism be made at this time,` that additional pressure would be admitted,

and automatically cut off, according tothe extent of' the movements of operation as outlined above. The release or decrease of 5 pressure is secured or accomplished by merely raising the exhaust valve 21 out of its seat, whereupon the air of the entiresystem will escape through the said valves and out Cthrough the ports 12a in the cap 12 of the 0 piston rod B. It will be seen that the reduction of pressure thus brought about .in the chamber 3 will cause the piston C to be raised by the spring expansion beneath it, .carrying the closed intake valve I4 with it, and keepingthe exhaust valve seat 19 which is chamfered in the h'eadof the tubular valve stem 15 inclose proximity tothe receding valve head 21, soy that should the Yraising of said-exhaust valve 21 cease, then the release of pressure would instantly cease, because of the seating of the valve 21 by the pressure of the main spring 5. It is also obvious that any leak of the applied air would be automatically replaced by the main spring 5 opening the intake valve .14, and allowing air to enter and replace the leakage, and by such replacement cause a movement of the piston C until t-he intake valve 14 wouldv again .be closed, the pressure on the operated valve assembly at the eye bolt 23 remaining constant. The graduation of pressure is determined by the extent of movement at the eye bolt 23 and the tension of the main springf. It is to be noted that the casing A and piston B together form a housing for the two pistons and thatl in said housing "an air pressure chamber is-formed between said pistons.'

Having thus described my invention, and

its operation I desire to secure by Letters Patent, and claim:

1. An automatic control valve colnprising a casing; a piston slidably carried in said casing; exhaust and intake valves operable by the movements of the piston; means to manually operate said valves in one direction; means to corivey airv to said valves; a spring to regulate the movement of said piston against the tension of which spring the piston is movable by i.the involved air pressure; means to utilize the movement of the pistonvto operate the said valves to automatically regulate -the amount of air pressure in said casing.

2. An 'air valve comprising a casing; a Vpiston operable within said casing; a spring to regulate the movements of said piston; a hollow piston rod attached to said piston; valves operable within. said piston rod; means to convey compressed -air against the head of said piston; means tomanually operate the valves to allow varying air pressures to pass them.

3. An air valve 'comprising a casing; a' piston operable therein and dividing `the interior of the casingK into two compart-, ments; a spring in one compartment to regulate the movement of said piston; a hollow piston rod attached at one end to said piston; a 'iexible connectionr between the casing and piston rod; coacting valve stems operable in s-aid piston rod; a valve on each of said stems either of which is adapted to, close when the other is open; and means to direct compressed air through said casing and hollow rod in either direction.

4. An air control mechanism comprising a casing, a piston operable therein and having a central valve seat opening; a spring to regulatey the movement of said piston; a

hollow piston rod having air ports in its Wall and with one vend attached to said piston; coacting valves operable in said piston rod either of which is adapted to open, when the other is closed; and means' to direct compressed air in either direction through said casing and piston rod.

5. An air control mechanismv comprising -a casingfhaving a hole in its side Wall; a piston operable in the casing; aspiral spring carried in the casing adapted to be compressed by said piston; a hollow piston rod secured to one face of said piston and having an air port in its Wall; an interior casing secured on the other face of' said piston and movable therewith; valve stems operable iny sairhpiston rod, a valve on each of said stems either of which is closed when the other is opened; a'flexible connection between the interiors of the rst mentioned casing' and j said piston rod; and. means" to direct compressed air through the rst mentioned casing and said piston rod.

6. An automatic control valve comprising a casing; a `piston operable therein having a central valve seat; a main spring to regulate theimovement of'said piston; a piston rod secured tosaid piston, and tubular in form with air ports in its wall; a flexible tube connecting a'chamber within said casing with the interior of said piston rod; valve stems operable in the piston rod; intake and exhaust valve heads carried on the stems; va spring in said piston rod to hold the intake valve normallyv seated in said central valve seat; means to manually opery ate the said valves; and means to direct comto convey compressed pressed air past the intake valve.

7. An air valve comprising a casing, a piston operable within said casing, a hollow piston rod attached to said piston, a valve operable within said piston rod, means air against one side of said piston, a spring acting upon said piston in opposition to the pressure of such air, anda common means `for manually regulating the supply of air to and vits exhaust from said casing.

8. An: air valve comprising a easing, a piston operable therein and dividing the interior of the casing into twocompartments, a spring in one of said compartments to regulate the movement of saidpiston, a hollow piston rodattaehed to saidv piston, and in communication with the other ofxsaid compartments, eoaeting valve .stems operable in said piston-rod,` a valveon each of said stems, either of which is adapted to close when the other is open, and means to direct compressed air through said casing and hollow rod in eitherl direction.

9. An air control mechanism, comprising a'casing having a hole4 in -its side wall, a piston opera-ble in the easing, a spiral spring 1n said casing adapted to `be compressed by means for delivering air to said casing 7o through said piston, coactingV valve stems operable in said piston rod, a valveon each of said stems either of which is closed when the other is opened, and means to direct compiston rod.

l0. An automatic control valve comprising a casing, a piston operable therein having a central valve seat, a spring to re ulate the rod secured to said piston, having communiair exhaust port, a pair of eoaeting valve stems operable in said piston rod, an intake `pressed air through said casing and said .movement of said piston, a tubu ar piston` 8) cation with said easlng and formed with anV valve carried by one of said stems, an exhaust valve earned by the other of said stems, a spring in said piston rod maintaining said intake valve normally seated in said central valve seat of the piston, means for manually operating compressed air past the intake valve.

'11. A control valve for -uid braking sysl tems comprising a cylindrical casing, a piston reciprocatory` in said easing, a tubular said valves, and meansy to directv stem connected to said piston and sliding through one end of the casing, means c011- neeting said stem to a source of fluid supply, a valve. seating in said stem and controlling a passage through said piston, a spring urging said valve to its seat, a control element extending through the opposite e'nd 'of said casing, and means operable by said element l within the casing for unseating said valve.

12.` A control valvevfor fiuid braking systems comprising a housing, a pair of pistons reciproeatory in said housing to and from eachother, said housing forming a fluid pressure chamber between said pistons, one of said pistons being formed with an inlet to and the other with pressure chamber, said housing `having an opening into saidehamher'for connection to a brake line, means for delivering a fluid under pressure to said inlet, means for opot saidlinlet forming piston from the other f piston, a valve member normally closing said inlet, movable from the inlet-forming piston to an open position and adapted tobe closed 1'20 an outlet from said fluid lposing fa predetermined resistance to travel 11.5

of said pistons being formed with an inlet to and the other with an outlet from said'` A forming piston from the other piston, a valve member controlling said outlet,/and means for controlling said Valve members in common.

14. A control valve for iluid braking systems comprising a housing, a pair of pistons reciprocatory in said housing to and from each other, said housing .forming a fluid` pressure chamber between said pistons, one of said pistons being formed with an inlet to and the other with an -outlet from said chamber, said housing forming a fluid pressure chamber between said pistons, one of 'saidrpistons being formed with an inlet to and the other with an outlet from said chamber, said housing having an opening into said chamber for connection With a brake line, means for delivering a Huid under pressure to said inlet, means for opposing a predetermined'resistance to travel of the inlet-forming piston from the other piston, a valve-member normally closing said inlet, movable vfrom the inletforming'piston to an open position and adapted to be closed by a travel of the inlet-forming'pis- `ton from the other piston, a valve member controlling said outlet, a stem carried by the outlet-forming piston projectingl toward said inlet valve member, and adapted to unseat the latter through actuation of said outlet-forming piston, and means for actuating the last-named piston. l

f 15. A control valve for fluid vbraking systems comprising a housing, a pair of pistons reciprocatory in said housing to and from each other, said housing forming a fluid pressure chamber between said pistons, one of said pistons being formed with an inlet to and the other with an outlet from said chamber, said housing having an opening into said chamber for connection With a brake line, means for delivering a luid under pressure to said inlet, a` pair of valve members seating toward each other to respectively vcontrol said inlet and outlet,

means for initially seating the` outlet-controlling valve member and for then actuating the outlet-forming piston toward the other piston, means for unseating the inlet-controlling valve member responsive to travel of the outlet-forming piston toward the other v piston, the inlet-controlling valve member being again engageable with its seat,

through actuation of the inletforming piston from` the other piston, and means opx said inlet-forming piston through an end Wall of said housing, means for delivering a fluid under pressure to said stem exteriorly of said housing, means for opposing a predetermined resistance to travel of the `inletforming piston from the other piston, a valve member normally closing said inlet, movable from .the inlet-forming piston to anopen position and adapted to be closed by a travel of the Ainlet-forming piston from the other piston, a valve member controlling said outlet, and means for controlling said valve members in common, acting through one of said valve members upon the other.

17. A control valve for fluid braking sys tems, comprising a fluid pressure chamber having opposite walls movable lto and from each other to expand and contract said chamber, and respectively formed with an inlet to and an outlet from said chamber, means for connecting said chamber with a brake line, means for delivering a fluid under pressure to said inlet, al pair of valve members seating toward each other to respectively control said inlet and outlet,

means for initially seating the outlet-controlling valve member and for then actuatingthe outlet-forming wall toward the opposed wall of the pressure chamber, means,

for unseating the inlet-controlling valve e member responsive to travel of the outletforming Wall toward the opposed wall, the inlet controlling valve member being again engageable with its seat through travel of the inlet-forming Wall from the other wall, and means opposing a predetermined resistance tol travel of the inlet-forming wall from the other Wall.

18. A control valve for fluid braking systems, comprising a luid pressure chamber having opposite Walls movable to and from each other, and respectively formed'with an inlet to and an outletl from said chamber means for connecting said chamber with a brake line, means for delivering a Huid under pressure to said inlet, a pair of valve members seating toward each other to respectively control said inlet and outlet, a steam connected to said outlet-forming wall,

lao

projecting into said chamber and adapted to actuate said inlet valve member, a common means for seating said outlet valve y member and for actuating said outlet-forming lvwall toward the inlet-forming wall to unseat the inlet valve member through said stem, the inlet valve member being adapted to again engage its seat responsive to travel of the inlet-forming wall from the outletforming wall, and` means opposing a predetermined resistance to such travel. 19. A control valve for uid brakin `systems, comprising a housing, a pair o pistons reciprocatory in said housing, to and from each other, herein termed the first and second pistons, jointly .forming a fluid pressure chamber, means for delivering a fluid under pressure to said chamber, means establishing a brake line `connection to said' i l 2o chamber, means for venting fluid from said chamber, a normally unseated valve member controlling the luid exhaust from said chamber,l a common means for manually seating the exhaust-controlling `valve mem- 5 ber and for `actuating the first piston, the second piston being adapted b its travel from the first piston to seat said delivery y controlling valve member, and means oppos-y ing a predetermined resistance to travel of the second piston from the rst one.

20. A control valve for fluid braking systems comprising a housing, means for delivering a fluid under pressure to said houslng,- means establishing a brake .line connec-v tion to said housing means for venting fluid from said housing, a valve member con-` trollingrthe fluid delivery to 'said housing, means for manually unseating said valve member, means opposing the iuid pressure 40 in said chamber to unseating of said valve member` and means for automatically reseating said'valvey member responsive to a predetermined fluid; pressure in said chamber.

21. A control valvegfor Ifluid braking sys- .45. tems, comprising a Huid pressure chamber having a fluid outlet and .having a ported wall, means for delivering a ii'uid `under pressure to the port of said wall, a valve member normally closing .said port, means 5,0 for manually ,unseatingJ said yalve member, saidy ported'fwall being outwardly movablev responsive to pressure `of lluid Within said chamber, and said valve member, when unseated, being engageable 'with its seat '55 through 4outward movement of said wall,

and means opposing apredetermined resistance to outward movement of said wall.

22. A, controlvalve for fluid braking systems, comprising a fluid pressure chamber 09 .having an inlet and an outlet port formed .in opposed'walls thereof, means for deliver'- ing a fluid under pressurejto salid inlet port,

valve members ,controlling said ports, means for ,manually controlling said. valvev mem- '55' berslin common, and means coacting'with said pressure chamber to effect seating of the inlet-controlling 'valve member responsive ,to apredetermined pressure in said chamber. v

23. A control valve for fluid braking systems, comprising a fluid p ressure.cl1amber,

having an'inlet and an outletlport formed in opposed Walls thereof, means `for delivering -a Huid under pressure to said inlet port, valve members controlling said ports, means for successively seating the outlet-controlling valve member and unseating the inletcontrolling valve member, and means coacting .with said pressure chamber to eect seating of the inlet valve member,responsive to a predetermined rise of pressure in said chamber. Y y

2K4. A control valve for fluid braking systems, comprising a fluid pressure chamber having opposed Walls respectively formed with an inletand an outlet to said chamber, i

the outlet-forming wall beingy movable to- Ward the opposite wall, means ordelivering a 'fiuid under pressure to said inlet, a common means.y lfor manually closing said outlet and for actuating the outlet-forming wall toward the opposite wall, means for normally closing said inlet, and meansfor opening said inlet responsive to actuation ofy the outlet-forming wall toward the opposite wall. v t

25. A controllvalve for fiuid braking sys- Y tems comprising a having opposed Walls respectively formed with 'an inlezt and an outlet to said chamber, the outlet-formingfwall being movable toward the'inlet-forming wall, means for delivering a fluid under `pressure toy said inlet,

a common means for manually closing said' outlet and for actuating the outlet-forming Wall toward the opposite wall, means for normally closing said inlet and means -carried by said outlet-forming wall within said chamber for opening said inlet uponfactation ofsaid outlet-forming wall toward the opposite` wall. Y'

26. A control valve for fluide braking systems comprising a fluidpressure lchamber having opposed walls movable to and from eachother' and respectively formed with anV inlet and 4an outlet tofsaid chamber,

means for delivering a fluid under pressure to said inlet, a common means for closing said outlet and actuating the outlet-Wall toward the inlet-wall, a` valvermember controlling said inlet means within said chamber for unseating said valve vmemberthrough inward actuation of the outlet-forming wall, and means? opposingy a` predetermined resistance to outward actuation of Vthe inletforming wall, whereby upon av predetermined risel of pressure in said chamber, consequent to unseating o f said valve member, reseating of said member 'is accomplished by outward yielding of the inlet-forming wall.

fluid pressure chamber ico nresistance to actuation o 27. A control valve for fluid braking systems comprising a fluid pressure chamber having opposed walls movable to'and from each other, one of said walls being formed with an inlet port, means for delivering a fluid under pressure to said port, a Valve member controlling said port, seating inwardly with respect to said pressure cham-v ber, lmeans carried interiorly of tlierpressure chamber by one of said opposed walls for unseating said valve member responsive to an actuation ofone'of said walls toward the other, and means opposin a predetermined the ported wall outwardly with respect to said, chamber, whereby upon a predetermined rise of pressure within said chamber, consequent to unseating of said ,valve member, reseating of said member is accomplished by outward yielding of said ported wall.

28. A control valve for fluid braking systems, comprising a fluid pressure chamber having an inlet and an outlet port formed in opposed walls thereof, means for delivering a fluid under pressureto said inlet port, valve members seating upon` said Walls and controlling said ports, a common actuating means for said valve members adapted to successively seat the outlet-controlling valve f `member and Vunseat the inlet-controlling valve member. y

i 29. A control valveI for fluid braking systems, comprising a fluid preure chamber having an inlet and an outlet port formed in op osed` walls thereof, means for-delivering a 'uid under pressure to saidcinlet port, valve members controlling said ports, seatin toward each other, the outlet-controlling valve member being adapted` for lactuation subsequent toits seating toward the other valve member, and means for actuating said valve members in common, effective to seat the outlet-controlling valve member and i then actuate it toward the inlet-controlling valve member and acting thrufrh theoutlet-controlling valve member, allier seating thereof, to unseat the inlet-controlling valve,

member. Y

30. In a control for fluid braking systems,

ythe combination with an e'xpansible fluid pressure chamber, and means forA delivering a fluid under pressure to said chamber and for dischar ing it therefrom, of means automatically limiting the admission of fluid to said chamber through its expansion in one direction, and means, opposing expansion of said chamber in another direction for exercising manual control of the fluid delivery.

31. In a control for fluid braking systems, the combination with an expansible fluid 'pressure chamber having an inlet and outlet, and means for delivering a fluid under pressure to said inlet, of means automatically limiting the delivery o f fluid to said inlet through expansion vof said chamber in one direction, and means opposed by expansion of said chamber in another. direction for successively closing said `outlet and opening said inlet.

32. In a control for fluid braking systems,l the combination with a fluid chamba-,means let, a ported piston slidable in said casing at one side of said outlet, means for delivermg -a fluid -under pressure to said outlet through the piston port, a valve member normally closing said piston port, seating in the direction of delivery of said fluid,

means for manually unseating said valve member, and means opposing a predetermined resistance to travel of said iston reverse tb the direction of fluid de ivery, said piston being movable, to reseat said valve member under a fluid pressure in said casmg adequate to overcome said predetermined resistance.

34. A control valve for fluid braking sysand from said inlet, and formed with an outlet, means :for delivermg a fluid under pressure to said inlet, a connnon means for manually closing said outlet and for actu-v atlng said piston toward said inlet, a valve- `member normally closing said inlet, and

outlet, means for delivering a fluid under pressure'tosaid inlet, a common means for manually closing said outlet and for actuating sald pistontoward said inlet, a valve member normally closing said inlet indeendently of said piston and means carried y said piston for unseating said valve member upon actuation of sald piston toward said inlet.

36. A control valve for fluid braking tems comprisin a housing, a pair of pistons slidable in sai housing to and from each other, forming with said housing a fluid pressure chamber, and .respectively formed with a'n inlet and an outlet to said chamber, means for delivering a fluid under pressure to said inlet, a common means for closing said outlet and actuating the outlet piston toward theinlet piston, a valve member controlling said inlet, means within said fluid pressure chamber for unseating said tems com rising 'a housing having a fluidv 4 inlet a piston sl1dable in said housing tol ius sysi valve member through actuation ofthe outlet piston toward theinlet piston, and means opposing a predetermined resistance to actuation of the inlet piston ,from the outlet piston, whereby upon a predeter- `mined rise of pressure in said chamber, consequent to unseatin of said valve member, the latter is adapte to be reseated by fluid pressure responsivev travelof the inlet piston. y

37. A- control valve for fluid braking systems com rising a. housing, a pair of pies` to said port, a valve member controlling said port, seating reversely to the direction yof fluid delivery, means carried between and by4 one of said pistons for unseating said valve member, responsive to actuation of one of said pistons toward the other, and means opposing a; redetermined resistance .to actuation of' sai ported Apiston from the other fpiston, whereby upon a predetermined pressure between said pistons consequent to unseatng of saidvalve member, the latter is reseated by fluid ressure responsive travel of said ported piston.

38. A control valve for fluid braking systems comprisin in said casing forming one wall of any ex'- pansible pressure chamber in said casing,

said pressure chamber, and said casing havingan outlet from said chamber,`m`eans, for delivering a fluid vunder pressure to said inlet, a spring 'opposingtravel of said piston in a. direction to expand said chamber, a

valve member controlling said inlet, and means for manually unseating said valve actuating said piston toward the fluid inlet of the pressure chamber, said means comprising` a control member disposed exteriorly of said casing and: subject to fluid pressure exerted upon said piston, and means for unseating the vinlet-controlling valve member responsiveto such actuation of said piston.

40.' A control' valve for fluid braking systems comprising `a housing, a piston slidable i in ysaid housing forming one Wall ofa fluid pressure chamber in said housing and formed with an outlet from said chamber, a valve member controlling said outlet, means for delivering a fluidundcr pressure to said ressure chamber, a valve ymember `contro ling tons'slida le in said housing to and from' each other, one Aof said pistons having a port,y means for delivering a fluid underpressure o a c asing, a piston slidable said piston being formed with an inlet to such delivery, a control element freely slidable in an end wall ofthe housing, adapted through actuation into the housiiigto seat the outlet-controlling valve member and to alctuate said piston toward the fluid inlet to t ie mit uid pressure acting on sai piston to thc housing exterior, and means for unseating the inlet-controlling valve member responsi've to actuation of said pistontoward the fluid inlet.

` 41. A control valve .for fluid braking systems, comprising a housing, means for admitting a fluid to said housing and for discharging it therefrom, a valve member in said casing exercising a control of the 'fluid flow through the housing, a. piston slidable in said housing and providing aseat for said valve member, and a4 control mechanism for said valve member, reacted upon by said iston, responsive to a opposite sides of the piston, and adapted to ressure chamber, and ada ted to transpressure differentia at transmit such reaction exteriorlyl of the 'housin i 42.

brake line, a piston slidable in said housing at` one lside of said opening and formed with a port forventing the brake line, a valve member controlling-said gort, and control means for said valve mem er, reacted-upon by said piston under brake line pressure and adapted t'o transmit such reaction exteriorly of-said housing. e

43. In a fluid braking system, a housing having an opening for connection 'with a brake line, a piston slidable in said housing, atv one side of said opening, and formed with a port for venting the brake line, a valve member controllin 'said lport, and a stein for seating said va housing. A4:4; Vn a fluid braking system, a fluidpressure chamber having an opening for connection with a brake line and having a wall yieldable under brake line pressure, beingl ported for venting brake h ne pressure, of a valve member controlling said port, and control means for said valve member reacted upon by said yieldable wall, when said valve member is seated, and providing for transmission of such reaction exteriorly of said chamber.

45. In a fluid braking system, a brake line pressure chamber having an opening for conneetion with a brake i opening for admitting an actuating fluid to said chamber, a valve member controlling said fluid admission'opening, one wall of said chamber being yie dably responsive `to a fluid braking system, a housing having an opening for connection with a ve member, reacted upon yby said piston under brake line pressure i,

ne and having anV said wall 8 Y l 17,402 f ressure'insaid chamber and being ported upon by said yieldable wall under pressure or venting the brake line,v a valve 'member in said chamber to oppose such pressureeto controlling said vent. port, and a muscular-Iy the muscular actuating el'ort. 1U actuable common control means for said Signed at Santa Monica, inthe county of l valve members, adapted to unseatwthe luid- Los Angeles, State ofCaliforniathis twenadmitting valve member upon .seatmg of the e tieth day of November, 1928. vent-controlling valve member, and reacted -ROBERT E. MITTQN. 

